Hypnosis and cognitive control has been an area of interested for researchers for decades. Researchers are concerned whether hypnosis is an altered state of consciousness or just a psychological state. Most of the studies in this area have been focusing on the changes in cognitive components under hypnosis, while control of body movements has not been widely explored.
The earlier studies suggested that hypnosis can lead to a dissociation between the physical aspects of movement execution and the intention to move. However, most recent studies have tried to determine whether the pre-planning and the intention to perform an act differ in the awake and hypnotic state. Still, these studies have not led to a full understanding of brain mechanisms during hypnosis.
A study conducted by Cesari et al. (2020) examined whether the motor system is differently activated when people imagine that they are executing activities in the awake and hypnotic state. The researchers also tried to find out whether activation differs between individuals who are considered less or more susceptible to hypnotic suggestions. The findings of this study suggest that imagining a movement in the hypnotic state leads to the modulation of corticospinal system excitability depending on a person’s susceptibility to hypnosis.
The researchers found that motor evoked potentials (MEP) amplitude between the imagery in hypnosis and rest were not different among the lows. They observed a difference in neurophysiological pattern, suggesting that corticospinal system activation during internal stimulation of actions can be determined by individual factors in both the awake and hypnotic state. The association between hypnotizability and motor control is dependent on the assumption that highs and lows differ in various respects, especially in cognitive ability and action-based ability.
The results of this study showed that the motor cortex is not altered during the resting state by being low or highly sensitive to hypnosis. When people are not engaged in any activity, motor cortex activation levels do not change in the awake and hypnotic state. However, during an action, motor cortex activation differs between the highs and the lows. More activation of certain cognitive elements is observed in the highs than in the lows (Cesari et al. 2020).
Deeley et al. (2013) applied suggestions and functional magnetic resonance imaging (fMRI) to examine the loss of control and awareness of movements in highly hypnotizable individuals. The researchers determined that loss of perceived control of movements was related to reduced connectivity between motor regions and supplementary motor area (SMA). Less activation in parietal cortices and insula was responsible for reduced awareness of involuntary movements.
These study results show that individuals’ sense of voluntary control of movements may be dependent on the simultaneous functional activities of SMA and motor systems. This offers a potential neural basis for reduced awareness.
References
Cesari, P., Modenese, M., Benedetti, S., Andani, M. E., & Fiorio, M. (2020). Hypnosis-induced modulation of corticospinal excitability during motor imagery. Scientific reports, 10(1), 1-9.
Deeley, Q., Walsh, E., Oakley, D. A., Bell, V., Koppel, C., Mehta, M. A., & Halligan, P. W. (2013). Using hypnotic suggestion to model loss of control and awareness of movements: an exploratory fMRI study. PLoS One, 8(10), e78324.
Melvin S. Marsh is a certified hypnotherapist serving Augusta GA and Statesboro GA. He performs hypnotherapy appointments both in person (although that is on hold due to covid) and worldwide virtually. He can be reached at www.afterhourshypnotherapy.com .
